Valves which are used in the food processing, biotech, pharmaceutical, and medical fields to control, mix, divert or meter fluids for industrial and research applications must be designed to operate in a sanitary manner and prevent contamination of the fluid product passing through the valve. A fluid valve used in the food processing, biotech, pharmaceutical and medical fields must therefore be inert to the system in which the valve is a part. The valve itself must not contaminate the fluid product, nor allow contamination of the fluid from sources either inside or outside of the system. Sources inside of the system can include the material of the valve itself or accumulated residue from cleaning or other fluids, including stale or contaminated fluid entrapped in spaces in the valve. In the case of mixing and diverting systems, such inside sources can also include other system fluids controlled by the valve. Because of leakage, slow or imprecise actuation or the presence of dead spaces which allow fluids to accumulate, cross contamination of the fluids in the system may occur.
Contamination from inside sources is a particular concern if the system must handle successive batches of fluids such as blood, where one or more batches may contain a deadly contaminant, such as the HIV virus. Entrapped residue of an earlier contaminated batch can contaminate later batches, with deadly consequences. Also, if the valve must handle fluids containing dangerous or deadly substances, like blood containing the HIV virus, it is important that the valve handle the fluid without contamination of the atmosphere, the area around the valve, or other parts of the system.
Contamination sources outside of the system can include germs, viruses or other tiny microorganism or contaminants in the atmosphere, or fluids or other substances used to actuate the valve. These contaminants may work their way into the fluid in the system through spaces or joints in the body of the valve.
In certain applications, such as when biofluids like blood or sensitive fluids containing proteins or enzymes are processed, it is also important that the valves do not stress the fluids with shear or other forces which would damage or otherwise detrimentally affect the integrity of the fluids as they pass through the valve.
As briefly mentioned above, another important consideration for food processing, biotech, pharmaceutical and medical applications is the accuracy and speed of the valve. Accurate and precise actuation prevents leakage across the valve seat which could cause cross contamination. Fast actuation also prevents cross contamination from unwanted mixing of system fluids. In addition to preventing unwanted mixing or contamination, accuracy and speed in valve actuation are important in maintaining accurate control of the fluids, especially if the valve is used for sanitary fill applications, or in combination with other valves in a manifold.
In many applications, it is also useful if the valve has precise metering capability to further provide accurate control of the fluid flow.
Reliability and long life are other important considerations. The valve should be able to cycle as many as one million times without failure or compromise of the sanitary condition of the system.
Because of the complexity of most fluid handling systems, particularly in the food processing, biotech, pharmaceutical and medical fields, it is also important that the valve be small, simple, easy to service and maintain, easy to clean, and easy to replace. Simplicity and reliability in a valve can significantly reduce the initial and life cost of a fluid handling system.
Further, many sanitary applications require that the valve have clean-in-place (CIP) and/or steam-in-place (SIP) capabilities.